Machine-Type Communication (MTC) which is a new communication concept is intended to organic combine various types of communication technologies, e.g., machine to machine communication, machine-controlled communication, human-machine interactive communication, mobile communication over the Internet, etc., to thereby drive the development of social production and life styles. Future human-to-human communication traffic is expected to potentially account for only ⅓ of the entire market of User Equipments (UEs), and MTC communication traffic is expected to account for a larger share of communications. MTC communication is also referred to as Machine-to-Machine (M2M) communication or the Internet of things.
The existing mobile communication network is designed, for example, the capacity of the network is determined, etc., for human-to-human communication. If the mobile communication network is required to support MTC communication, then the mechanism of the mobile communication system needs to be optimized according to the characteristic of MTC communication for the purpose of better MTC communication with little or no influence upon traditional human-to-human communication.
A Cell Broadcast Service (CBS) is a mechanism supported by both the existing Universal Mobile Telecommunication System Terrestrial Radio Access Network (UTRAN) system and the existing Global System for Mobile Communications (GSM) to broadcast the same contents to UEs in some area. The CBS involves entities including a Cell Broadcast Center (CBC) and a Cell Broadcast Entity (CBE), where the CBC is regarded as an entity in a core network. The broadcasted contents are referred to as CBS information generated by the CBE. The CBS information is broadcasted in a predefined area referred to as a CBS service area. The CBS service area may include one cell or several cells or even the entire Public Land Mobile Network (PLMN). The CBS service area is determined by the subscription of an information provider with a network operator and notified by the CBC to the Radio Access Network (RAN) side. The CBS information is broadcasted without any acknowledgment.
The warning message delivery technology is currently supported in the Long Term Evolution (LTE) system. Within this technology which has similar mechanism with the CBS, warning information without any acknowledgement can also be transmitted to UEs in a specific area. At the RAN side, the UEs need to obtain the warning information broadcasted by the network side by obtaining a system message or by obtaining the system message as triggered by a paging message.
In the UMTS system, downlink broadcast data is transmitted over a Control Traffic Channel (CTCH), and carried respectively over a Forward Access Channel (FACH) and a Secondary Common Control Physical Channel (SCCPCH) among transport channels and physical channels, in the existing CBS mechanism. Due to limited capacities of the FACH and the SCCPCH, a significant amount of downlink data is transmitted with a risk of an unsatisfactory Quality of Service (QoS); and also a random access setup message is carried over the FACH, and when an FACH resource is occupied by CTCH traffic, there are less resources of the FACH available to a random access, thus lowering the success ratio of an access by a UE. If transmission is performed with group-cast also in the CBS mechanism, then the FACH resources may be further limited.
In the LTE system, there is currently only a mechanism for transmitting a warning message as system information. If group-cast data is also transmitted as system information, then there will be inevitably a significant influence on the existing mechanism for scheduling system information, so that the system information may be scheduled and updated out of order when there is frequent group-cast, thus making it complex for the UE to fetch the system information.
In summary, in the UMTS system, a group-cast message can not be transmitted due to the limited FACH; and in the LTE system, if group-cast data is transmitted as system information, then there may be significant influence upon the existing mechanism for scheduling system information.